This invention relates generally to electronic devices such as capacitors and metal-insulator-field effect transistors (MISFETs), and more particularly the invention relates to dielectric material used therein.
The rapid reduction in cell size of dynamic random access memories (DRAM) has necessitated innovative cell structures and highly reliable ultra thin dielectrics. Silicon nitride (Si.sub.3 N.sub.4) remains the most practical capacitor dielectric from a module integration and manufacturing perspective due to its process simplicity. However, electrical properties of the ultra thin film capacitors degrade due to the bottom native oxides. Rapid-thermal NH.sub.3 -nitridation (RTN) in situ HF cleaning, and in situ rapid-thermal multiprocessing can remove the native oxides, leading to the improvement of film quality. Reoxidation of Si.sub.3 N.sub.4 film, typically in an oxygen ambient, is used to reduce leakage current and pinhole density.
The MIS transistor is used in ultra large scale integrated (ULSI) microelectronic circuits such as DRAMs. The transistor includes a current carrier source region formed in a surface of a semiconductor (e.g., silicon) body, a carrier drain region formed in the surface and spaced from the source, and a channel region between the source and drain in which the current carriers flow. Overlying the channel region and aligned with the edges of the source and drain is a gate electrode which is physically and electrically separated from the channel by a dielectric layer. Typically, the dielectric comprises a silicon oxide.
The present invention is directed to providing high quality ultra thin dielectric layers and capacitors, field effect transistors, and other electronic devices.